Armature Origins Wrong?
Change the origins of the flower center and petals and stem by using 

[origin to geometry]

as depicted in the image above.

The 


flower center 
flowers petals 
stem


should be quickly changed to have their origin modified as above or with the mesh itself or perimeter.  I see your petals have the correct parent of the flower center. Suggestion. Names of objects can be quickly improved The visual stem mesh should have a name like [stem]. The flower center should/could have the [stem] as parent, depending on animation complexity.



Above image shows more correct placement of origins.  Your can manually improve the flower petal origins if that suits your tastes.

Currently your origins are not in the correct place.